You can deploy Instant Messaging Service in a variety of configurations to meet any company's needs. Your company's ideal Instant Messaging topology can be like one of the examples shown here, or it can include a combination of the features shown in two or more of these examples. The configuration you use is determined by your organization's:
The following examples show typical configurations and provide a starting point for you to plan your topology.
Note For planning purposes, the approximate capacity for an Instant Messaging home server is 10,000 online users. The approximate capacity for an Instant Messaging router is 20,000 online users.
The following might be used by a small to medium-sized educational institution with:
This deployment might be used by an ISP, and is characterized by:
This topology provides Instant Messaging for an organization with:
An organization using this topology places Instant Messaging routers that have Internet connectivity for incoming messages in a perimeter network, which is sometimes called a demilitarized zone. The perimeter network is designed to provide security.
Important No matter how tight the security is on an external perimeter network, there is still a risk of exposure from an external or internal source. You need a plan that will help you react to a violation of security policy if one occurs.
This topology can be used by any size organization. An HTTP reverse proxy server is placed between the Internet and the Instant Messaging routers, usually instead of a firewall. Outgoing messages are routed through a proxy server. The reverse proxy server accepts all inbound Instant Messaging traffic and relays it to the Instant Messaging routers. A reverse proxy server is similar to a regular HTTP proxy server normally used for outbound traffic; in this configuration it accepts connection requests from the outside and relays them inside.
This topology illustrates how you configure an organization with multiple e-mail domains. In this example:
For organizations with more than one Windows 2000 Server forest, each forest is a separate Instant Messaging domain, and should be treated as an independent Instant Messaging installation.
This topology might be used by an organization dispersed across more than one continent. For this example:
Related TopicsService Architecture